Sliding on a snowy slope is not part of our original human composition since our evolution was oriented towards the firm ground. Balance in sliding on snow, even if it can be spontaneous and exciting for some, must be learned by the majority of people. When a displacement of our body’s center of mass (CoM) occurs, the permanent action of our vestibular system produces reactions that help to recover it. Our visual and vestibular senses during balance while sliding on snow are related: some skiers rely on visual information while others on the vestibular system.
Our instability, in addition to the narrow base of support (BoS), and taking into account that the 2/3rds. of our corporeal mass is located in the upper body, comes from motion on a sliding element as snow. The sense of balance while sliding appears when perceiving the relationship with space and gravity through the ski-snow connection. The causes that may affect our balance control while sliding could be deficient posture, excessive muscle tension, movement limitations or sensory and emotional interferences.
Each one of us may react differently to similar situations. In the case of the beginner who experiences sliding on snow for the first time, senses that the skis tend to ‘escape’ from underneath. Thus, the first responses to recover are reflex, since he is not ready yet in carrying out a voluntary balance control.
In a certain way, this mechanism is characterized by energy saving, because the reflex does not pass by brain control, being transmitted directly from the spinal cord to nerve endings (peripheral nervous system). Gradually, balance maintenance and/or recovery is manifested through reactions based on muscle contractions, with some voluntary control that depends on each one’s emotionality.
These contractions are not easy to control since they are the result of nervous discharges. Later, as we strengthen our sliding experiences, we develop an anticipatory process in which, due to the implementation of our emotional regulation (less anxiety or fear), we accede to a flexible control that allow us being able to incorporate efficient body movements.
Considering that our fluctuation point in balancing is located at our ankles, it is normal in skiing that fore-aft, lateral, and diagonal oscillations exist associated with body rotation. These are created by our own actions while moving and modifying our posture by taking advantage or by resisting external forces.
Oscillations produce a circle of losing and recovering balance, in which our balance is ‘lost’ at the start of the turn to then recover it right after. In skiing we oscillate multi-directionally to then detect a momentary balanced situation that will be immediately absent right after.
To optimize our balance, we should accept our body oscillations learning how to control them by executing adjustments based on the proprioceptive information that these oscillations generate. Minor oscillations are usually detected by our feet, while higher ones by our vestibular system. Our goal should be to reduce them through controlling our feet’s center of pressure (CoP), which forms part of our base of support, making adjustments at ankles level, activating lower leg muscles like soleus and tibialis anterior. These oscillations are caused by variations in slope inclination, as well as skis-snow friction variations producing accelerations and decelerations due to external forces.
It is observed that the beginner tenses his body to minimize body oscillations, while the expert knows that oscillations are part of skiing, taking advantage of them by coordinating muscle adjustments. When staying upright, we observe that oscillations tend to occur at our ankles joint, but while tilting forward, oscillations take place around our hips joint. It must also be considered that using different skis or boots, skiing different slope inclinations, snow types or uneven terrain, we will perceive a variation in the oscillations we are used to.
We can conclude that the responses to balance and acceleration about sliding on snow also depend on the influence of the emotional reactions of each skier. Then, with this in mind, we can agree that each skier’s progress is inversely proportional to the sliding fear he experiences.
